Autophagy-related genes from a tick, Haemaphysalis longicornis

Autophagy. 2008 Jan;4(1):79-81. doi: 10.4161/auto.5143. Epub 2007 Oct 9.


Ticks are gorging-fasting organisms;(1) their life cycle is characterized by alternate off-host (starvation) and on-host (meal) conditions. Their generation time is estimated in several years and many ticks spend more than 95% of their life off the host. They seem to have a unique strategy to endure the off-host state for a long period. Thus, we focused on autophagy, which is induced by starvation and is essential for extension of the lifespan,(2-4) and hypothesized that ticks also have a system of autophagy to overcome the starved condition. Recently, we showed the existence of a homologue of an ATG gene, ATG12, and its expression pattern from nymphal to adult stages in a three-host tick, Haemaphysalis longicornis. The expression level of HlATG12 was downregulated at the beginning of feeding and was highest at 3 months after engorgement. In addition, the HlAtg12 protein was localized to the region around granule-like structures within midgut cells of unfed adults. These results indicate that HlATG12 functions during unfed stages. Here, a potential role of autophagy in unfed ticks is discussed with regard to reports in other animals, such as yeast, mammal, and fruit fly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / genetics*
  • Female
  • Food Deprivation
  • Genes, Insect
  • Life Cycle Stages*
  • Ticks* / genetics
  • Ticks* / physiology